This restriction certainly does not apply to the situation described in ref. [1]}, which, taken at face value, implies e.g. a shift of some \(250 K\)  from \(50 K\)  to room temperature for the critical temperature of \(YBa_{2}Cu_{3}O_{6.5}\)  after a THz pulse. So one must understand Eq. (5) as describing the "small Q" regime, where Eq. (6) is satisfied, and not the regime of intense THz pumping that the experiments access. The quotation marks around "small Q" are justified by the circumstance that, according to ref. [2]}, the \(250 K\)  rise in \(T_c\)  corresponds to a \(0.63 \%\)  elongation of the intra-Cu bilayer distance, which in other contexts one could call a small distortion.
